Fix errors found with proguard

By default disable progaurd as enabling it will remove all java
classes marked as unused but they may be used by native. To enable
proguard need proguard.cfg file to have keep rules for Java
classes which are either used by native or dynamically called.

Change-Id: I54e990d9b829be54656a5904cb1427a2d2867234
2 files changed